Introduction
Secondary
hemophagocytic
lymphohistiocytosis (SHLH) without familial history or known genetic
predisposition is considered an overwhelming and life-threatening
systemic inflammatory syndrome. SHLH can be related to
infectious diseases (IAHS),
associated with autoimmune diseases (MAS), or due to malignancies
(M-HLH). Over half of all the SHLH cases culminate in multiple organ
failure, with up to 86% requiring admission to the intensive care unit
(ICU). Among ICU patients, SHLH are usually triggered by infection
disease and sepsis[1].
Appling initial chemotherapy including etoposide combined with steroids
and cyclosporine A in a timely fashion is important for survival.
However, despite advances and improvements in chemotherapy, in 20% of
cases, SHLH patients do not respond to conventional treatment, many of
these patients die of rapid deterioration due to severe sepsis and
MODS[2]. The mortality rate
in
SHLH with MODS patients has remained unacceptably high, at greater than
50% in some studies[3]. In children, SHLH may present with more
acute fulminant manifestations and the incidence of MODS was higher than
adults[4,5]. Poor outcomes in children with SHLH-associated MODS
have led to a call for action to improve early diagnosis, institute new
preventive measures, and develop new treatments to improve clinical
outcomes.
Recently, Continuous renal
replacement therapy (CRRT) has evolved from standard renal replacement
therapy into an especially unique role in “mutiple-organ support
technology” for MODS patients. CRRT is very effective in removal of
inflammatory
mediators, as well as maintaining fluid balance and hemodynamic
stability for critical ill patients[6]. Aggressive application of
CRRT was found to decrease mortality in adult patients with septic shock
and MODS[7]. SHLH patients may need CRRT for renal replacement,
inflammatory mediator or cytokine removal. Similarly, CRRT is an
important treatment for severe SHLH patients, although there are
insufficient studies regarding the efficacy and indications for CRRT in
the pediatric HLH ICU population. We previously found that high-volume
hemofiltration may improve organ function by decreasing tumor necrosis
factor-α and interleukin-6, which might be an effective adjunctive
treatment in secondary hemophagocytic lymphohistiocytosis[8]. The
mortality among children with MODS requiring CRRT continues to be very
high. Therefore, it is important for physicians to identify patients in
whom aggressive treatment may offer recovery or those who may benefit
from CRRT.
To the best of our knowledge, there are no available data on outcomes of
critically ill children with SHLH and MODS
receiving CRRT and identifying
relevant prognostic factors. In this study, we initially analyzed
survival outcomes among 52 pediatric patients with SHLH and MODS
receiving CRRT. Then we assessed predictive factors for survival
outcome. PRISM scores were used to
assess whether the observed effect was independent of severity of
illness.